Smokers wanting to kick the habit needn’t be too worried about gaining a lot of weight after quitting, according to newly published University of Otago research.

The findings emerge from the world-renowned Dunedin Multidisciplinary Health and Development Study, which has closely followed the progress of around 1,000 people born in Dunedin in 1972-73. Smoking habits and weight were measured at regular intervals from 15 to 38 years old. About one third of the group were smokers at age 21, and by age 38 around 40% of these people had quit.

Over the 17-year follow up, the quitters’ weight returned to the same level as people of similar age who had never smoked in the first place. Furthermore, they gained only a relatively small amount of weight - around 5kg - compared to people who carried on smoking. The findings were the same for both men and women.

Lindsay Robertson, who led the research, says some earlier research had suggested that people might gain large amounts of weight after quitting, but many of these studies were not very reliable.

“We hope that our findings will encourage people who are thinking about quitting. They should not be put off by the fear of putting on large amounts of weight. It is important to be aware that a small weight gain is unlikely to offset the health benefits of quitting,” says Miss Robertson.

The researchers also found that being a smoker did not prevent long-term weight gain. All groups in the Dunedin Study tended to put on weight over time, regardless of their smoking status, she says.

The study, titled “Smoking Cessation and Subsequent Weight Change” was authored by Miss Robertson, Professor Rob McGee (Cancer Society Social and Behavioural Research Unit) and Associate Professor Bob Hancox (Dunedin Multidisciplinary Health and Development Study), in the Department of Preventive and Social Medicine. It is published online in the journal Nicotine & Tobacco Research.

The Dunedin Study is supported by the Health Research Council of New Zealand.

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